Insulated grounding sheath connectors



P 2 1960 M. c. LOGAN 2,954,420

INSULATED GROUNDING SHEATH CONNECTORS Filed Dec. 3, 1957 INVENTOR. M02; C 106/! E'A WA 6*.

tates atent @fiice Patented Sept. 27, 1960 INSULATED GROUNDING SHEATH CONNECTORS Maurus C. Logan, Elizabeth, NJ., assignor to The Thomas & Betts C0,, Elizabeth, NJ., a corporation of New Jersey Filed Dec. 3, 1957, Ser. No. 700,512

Claims. (Cl. 174-75) The invention relates to devices for grounding electric cables and more particularly to a unitary, insulated, grounding sheath connector whereby the high frequency shield of coaxial cable conductors and the like may be readily connected to ground without adversely affecting the cable structure or its electrical characteristics.

The invention has particular reference to an insulated annular connector for shielded electric cables whereby a connection may be made from the braided metallic shield of a cable to ground by means of an insulated wire conductor having a stripped end portion thereof intruded into either end of the connector radially of and in crimped relation with an exposed end portion of the metallic shield after the connector has been fitted on an end portion of the cable.

More specifically, the invention resides in a unitary, annular connector for shielded coaxial cables wherein a pair of tubular metallic members are locked within an insulating cap in radially spaced, concentric relation for receiving therebetween in telescopic relation, an exposed end portion of the cable shield which is subsequently clamped between the tubular members by crimping the outer tubular member thereon through the insulating cap, the inner tubular member receiving the core portion of the cable therethrough while serving as a. mandrel for crimping the exposed end portion of its metallic shield thereon.

Similar insulated grounding sheath connectors as known heretofore possessed certain disadvantages in that difiiculty was experienced in entering an exposed end portion of the high frequency shield of a coaxial cable into the open end of a double-walled shell, formed by reversely drawing a metal sleeve upon itself, when secured in an insulating sleeve, without compacting the braided metallic shield at the entrance thereof, and thus not properly extended thereinto for crimping the shell thereon through its insulating sleeve in approved manner. Moreover, such double-Walled annular shells preeluded the advantages of crimping the exposed end portion of a braided metallic cable shield between a soft metal sleeve and a relatively hard metal sleeve of different diameters, when telescoped in annularly spaced concentric relation.

Accordingly, it is an object of the invention to provide an improved, insulated grounding sheath connector for coaxial electric cables which obviates the aforesaid disadvantages.

Another object of the invention is to provide an improved grounding sheath connector which does not impair a shielded electric cable structure or its electrical characteristics.

A further object of the invention is to provide an improved insulated grounding sheath connector which is adapted to be crimped on an electric cable conductor without causing separation between its conductive elements and insulating cap.

Another object of the invention is to provide an insulated grounding sheath connector as specified, wherein an exposed end of a braided metallic cable shield is visible from one end of the connector after the cable has been intruded thereinto from its opposite end.

A further object of the invention is to provide an insulated grounding sheath connector as specified which permits of the insertion of the stripped end of an insulated wire conductor into either end of the connector radially of the outer periphery of an exposed portion of a braided metallic cable shield for the connection thereof to ground.

Another object of the invention is to provide an improved grounding sheath connector as specified which is adapted for receiving an end portion of a coaxial cable therethrough with an exposed end portion of its braided metallic shield disposed in a uniform annular passage formed by a pair of metal sleeves differing in diameter and anchored within an insulating cap in concentric telescopic relation.

With the above and other objects in view, the invention resides in the novel construction, combination and arrangement of parts, the novel features of which are set forth with particularity in the appended claims, the invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, being best understood from the following description of a specific embodiment thereof, when taken in connection with-the accompanying drawing, in which:

Fig. 1 is a View in perspective showing the improved grounding sheath connector as secured on an end portion of a coaxial cable and showing a conductor as leading to ground from either end of the connector in accordance with the invention;

Fig. 1 is a longitudinal sectional view of a prior art insulated grounding sheath connector, wherein a single metal sleeve, reversely drawn upon itself to form a doublewalled shell, is utilized for receiving an end portion of a braided metallic cable shield therein;

Fig. 2 is an elevational view of the front end of the improved grounding sheath connector as seen in Fig. 1;

Fig. 3 is a longitudinal sectional View through the connector insulating cap per se;

Fig. 4 is a longitudinal sectional view through the connector per se;

Fig. 5 is an elevational view of the rear end of the connector as seen in Fig. 4;

Fig. 6 is a longitudinal sectional view showing the improved grounding sheath connector as secured on a stripped end portion of a coaxial cable with the exposed end portion of its braided metallic shield including the stripped end of an insulated wire conductor intruded into either or both ends of the connector, crimped between a pair of metal sleeves forming a part of the connector; and

Fig. 7 is a transverse sectional view taken on the line 7-7 of Fig. 6.

Referring to the drawing, Fig. 1 illustrates an improved insulated grounding sheath cable connector 10, in which a pair of metal sleeves 12 and 14, secured in concentric, annularly spaced telescopic relation within an insulating cap 1;, form a straight annular recess 18, therebetween for the intrusion therein of an exposed end portion of a braided metallic cable shield 20, the opposite end of said annular recess 18 communicating with a plurality of angularly spaced, rectangular slots 22 extending radially from the defining periphery of a central outlet opening 24 formed in the closed end of the insulating cap 16, whereby the stripped end of an insulated wire conductor may be inserted into its closed end as well as into its open end, to connect the intruded cable shield to ground.

For purposes of comparison, Fig. 1 illustrates a known form of insulated cable sheath connector B, in which a single metal sleeve C has been reversely drawn upon itself to form a double-walled shell D, for the intrusion therein of an end portion of a braided metallic cable shield, the closed rounded end of the shell D being provided with a pair of small, diametrically opposite openings E for the insertion in either opening of a stripped end of an insulated wire conductor (not shown) to effect a connection with the intruded end of the metallic cable shield.

In accordance with the invention and as best shown in Figs. 3 and 4, the improved, insulated grounding sheath connector, generally indicated at 10, comprises an insulating cap 16, molded of nylon or the like, for example, presenting an axial bore 26, terminating at the open end thereof in a counterbore 28 which is provided on its periphery with a plurality of angularly spaced, convex projections 30, with their convex surfaces disposed lengthwise of the axial center of said insulating cap 16. The closed end of the cap 16 is provided with an internal axially extending cylindrical boss 32, having a smaller diameter than the axial bore 26, whereby an annular recess 34 is formed therebetween from the free end of the boss 32, to the closed end of the insulating cap 16, for a purpose hereinafter described.

As best shown in Fig. 3, the axial boss 32, formed within the insulating cap 16, is provided with a central opening 36 therethrough and said opening provided with a counterbore 38 extending from its inner end to a point short of the outer face of the closed end of the insulating cap 16, for a purpose also to be hereinafter described. The closed end of the insulating cap 16 is further provided with a plurality of angularly spaced rectangular slots 22, extending radially from the defining periphery of the central opening 36 therein to a point corresponding to the outer diameter of the axial boss 32, extending into the bore 28 from the closed end of the cap 16, whereby the annular recess 34, formed between the bore 28 and boss 32, may be seen from the closed end of the cap 16 by reason of the radial slots 22 therein.

Further in accordance with the invention and as best shown in Fig. 4, a pair of metal sleeves 12 and 14, as aforesaid, are secured in the insulating cap 16. The sleeve 12 of hard copper having the smallest outer diameter and its opposite ends internally chamfered, as at 40, is force-fitted into the counterbore 38 formed in the axial boss 32 within the cap 16, until its intruded end seats on the shoulder formed between one end of the counterbore 38 and the central opening 36 in the closed end of the cap 16, the length of the sleeve 12 being such that it extends toward the open end of the cap 16, at least to the convex projections 30, formed within the counterbore 38 at the open end thereof.

Thelarger metal sleeve 14, of soft copper and having its opposite ends also internally chamfered, as at 42, is force-fitted into the double-walled annular recess 34, formed between the boss 32 and the bore 34 within the cap 16, the length of the sleeve 14 being such that its free end extends to a point adjacent the inner end of the convex projections 30 formed inwardly of the open end of the cap 16. After the sleeve 14 has been seated on the bottom of the annular recess 34, axial pressure thereon is continued to flare its free end outwardly to the diameter of the counterbore 28, in the open end of the cap 16, whereby the sleeve 14 is prevented from being accidentally withdrawn from the cap 16, when in use, by the convex projections 30, as will be understood.

As clearly shown in Fig. 6, the improved insulated grounding sheath connector is attached to a shielded coaxial cable or the like, for example, as indicated at 44, after the metallic shield 20 has been properly exposed. In attaching the grounding connector thereto the projecting core 46 of the cable 44 is initially inserted in the central metal sleeve 12 until the free end of said sleeve approaches the end of the metallic shield 20, whereupon the metallic shield 20 is passed onto and over the metal sleeve 12, and movement of the connector 10 over the exposed end portion of the cable 44 continued until the exposed core 46 of the cable 44 extends through the central opening 36 in the closed end of the connector 10, and the exposed end portion of the metallic shield 20 intruded between the spaced metal sleeves 12 and 14, as will be understood.

After the improved grounding connector 10 has been so attached to the exposed end portion of a coaxial cable 44-, a stripped end of an insulated wire conductor 48 is subsequently intruded, either into one of the slots 22, in the closed end of the connector 10, or between the outer periphery of the intruded portion of the metallic shield 20 and the inner diameter of the metal sleeve 14, from the opposite open end of the connector, to provide a connection from the metallic shield 20 to ground. Finally, the soft metal sleeve 14 is crimped, as in Fig. 7, through the nylon cap 16 onto the intruded portion of the metallic shield 20, including the intruded bare end of the insulated wire conductor 48, the hard copper sleeve 12 serving as a mandrel which retains its circular form in the crimping of the intruded end portion of the metallic shield between the respective metal sleeves, the crimp imposed on the soft copper sleeve 14 being of hexagonal configuration with the bare end of the wire conductor 48 inserted therebetween secured in one of the corner portions of the hexagonally crimped sleeve 14 and the braided metallic shield 20, as exemplified in Fig. 7.

The radially extending slots 36, provided in the closed end of the insulating cap 16, as hereinbefore described, provide for the visual inspection of the exposed end of the braided metallic shield 20, after it has been intruded between the metal sleeves 12 and 14 within the cap 16; for the insertion of the bare end of an insulated wire conductor 48 between the metallic shield 20 and inner periphery of the metal sleeve 14; for rendering the closed end of the insulating cap 16 substantially flexible, whereby a crimping pressure exerted on the metal sleeve 14 through the insulating nylon cap 16 does not operate to deform the cylindrical configuration of the metal sleeve 12; and also tends to obviate the possibility of relative movement occurring between the cap 16 and either of the metal sleeves 12 and 14, during a crimping operation.

From the foregoing description, taken in connection with the drawing, it will be readily apparent that the improved insulated, grounding sheath connector 10, not only provides an approved, simple and efficient electrical and mechanical connection for grounding braided metallic cable shields, but also forms an enclosure on and about an exposed end portion of a coaxial cable which lends a finished appearance thereto.

While the invention has been illustrated and described with respect to a preferred embodiment thereof, it is to be expressly understood that various changes and modifications may be made therein without departing from the inventive concept underlying the same. Therefore, the invention is not to be limited except as is necessitated by the prior art and the scope of the appended claims.

I claim:

1. An electrical connector adapted for grounding the high-frequency shield of an electric cable comprising an insulating cap having a central opening through its closed end, means formed internally of said cap providing a counterbore in continuation of said central opening and an annular recess between said means and the inner periphery of said cap, a pair of metal sleeves differing in diameter each having one end portion thereof forcefitted respectively in said counterbore and said annular recess in annularly spaced telescopic relation for receiving an exposed end port-ion of said cable shield between the opposed peripheries of the opposite end portions of said sleeves, with the core portion of said cable extended through the inner one of said sleeves and the central opening in the closed end of said cap, and means formed radially of the central opening in said cap communicating a with the annular space between said sleeves adapted for inserting a bare conductor end portion into said cap in surface-contacting engagement with an exposed cable shield and the inner periphery of the outer one of said sleeves.

2. An electrical connector adapted for grounding the high-frequency shield of an electric cable comprising an insulating cap having a central opening through its closed end, means formed internally of said cap providing a counterbore in continuation of said central opening and an annular recess between said counterbore and the inner periphery of said cap, a pair of metal sleeves differing in diameter and length, each having one end portion thereof force-fitted respectively in said counterbore and said annular recess for receiving an exposed end portion of said cable shield on the inner one of said sleeves with the core portion of said cable extending through the inner sleeve and the central opening in the closed end of said cap, and means formed radially of said central opening in communicating with the annular space between said sleeves for inserting a wire conductor into said cap from its closed end into contacting engagement with the outer periphery of an exposed cable shield and the inner periphery of the outer one of said sleeves, the free end of the inner sleeve extending beyond the free end of the outer sleeve for centering a cable shield within the open end of said cap in advance of the outer one of said sleeves.

3. An electrical connector adapted for grounding the high-frequency shield of an electric cable comprising an insulating cap having a central opening through its closed end for receiving an exposed core portion of a cable therethrough, annular means formed internally of said cap providing a counterbore in continuation of said central opening and forming an annular recess between the inner periphery of said cap and the outer periphery of said annular means, a pair of metal sleeves differing in diameter each having one end portion thereof forcefitted respectively in said counterbore and said annular recess in annularly spaced telescopic relation, said metal sleeves differing in length and being internally chamfered at their free ends to facilitate entry of an exposed portion of a cable shield therebetween within said cap.

4. An electrical connector adapted for grounding the high-frequency shield of an electric cable comprising a cap of insulating material having a central opening through its closed end for receiving an exposed core portion of a cable therethrough, annular means formed internally of said cap providing a counterbore in continuation of said central opem'ng and an annular recess within said cap in concentric relation therewith, a pair of metal sleeves differing in diameter each having one end portion thereof force-fitted respectively in said counterbore and said annular recess in spaced telescopic relation for receiving an exposed end portion of a cable shield therebetween, means formed within the open end of said cap adapted for preventing relative movement of the outer one of said metal sleeves, said outer sleeve having its free end portion flared outwardly into abutting relation with said last-named means, and means formed in the closed end of said cap radially of said central opening adapted for the insertion of a stripped end of an insulated wire conductor between said metal sleeves, said metal sleeves being internally chamfered at their free ends and the inner one of said sleeves having a greater length and hardness than said outer sleeve to facilitate entry of an exposed portion of a cable shield therebetween and the crimping of said outer sleeve on said cable shield and said wire conductor through said insulating cap.

5. An electrical connector adapted for grounding the high-frequency shield of an electric cable comprising a cap of insulating material having a central opening through its closedend for receiving an exposed core portion of a cable therethrough, annular means formed in ternally of said cap providing a counterbore in continuation of said central opening and an annular recess within said cap in concentric relation, a pair of metal sleeves differing in diameter each having one end portion thereof force-fitted respectively in said counterbore and said annular recess in spaced telescopic relation for receiving an exposed end portion of a cable shield therebetween, the outer one of said sleeves having its free end portion flared outwardly to the inner diameter of the open end of said cap, means formed within the open end of said cap abutting the flared end of said outer sleeve to prevent relative movement thereof, and means formed in the closed end of said cap radially of said central opening adapted for the insertion of a stripped end of an insulated wire conductor between said metal sleeves, said metal sleeves being internally chamfered at their free ends and the inner one of said sleeves having a greater length and hardness than said outer sleeve to facilitate entry of an exposed end portion of a cable shield therebetween and the crimping of said outer sleeve on said cable shield and said wire conductor through said insulating cap.

References Cited in the file of this patent UNITED STATES PATENTS Dupre Dec. 26, 1950 Ustin Jan. 20, 1959 

